News Archive

Dr. Morcos Metry presents a research paper at the 2nd International Conference on Photovoltaic Science and Technology (PVCON).

Postdoctoral Researcher Dr. Morcos Metry and Ph.D. students Ms. Sawsan Shukri and Mr. Lance Alpuerto presented their paper entitled “Sizing of Differential Power Processing Converters Based on In-Situ Meteorological Data for Non-Planar Photovoltaic Applications” at the 2nd International Conference on Photovoltaic Science and Technology. The workshop, which was held virtually 30 November through 2 December 2020, was originally scheduled to be in-person in Ankara, TURKEY.

The paper develops a framework for designing power electronics converters for non-planar photovoltaic (PV) structures. The paper looks into the morphology of the PV structure, in-situ meteorological data, and models of current mismatch between neighboring PVs. The benefit of this study is the design of power electronics for non-planar PV that are both reliable and cost-effective.

This publication is based on research supported by the US Army Research Laboratory through the National Science Foundation Industry/University Cooperative Research Center for Next Generation Photovoltaics (IIP-1624539). This publication was also made possible in part by PDRA grant # 5-0422-19004 from the Qatar National Research Fund (a member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors.

Safin Bayes presents a research paper at the 2nd International Conference on Photovoltaic Science and Technology (PVCON).

Undergraduate research assistant Mr. Safin H. Bayes and Ph.D. student Sawsan Shukri presented their paper entitled “Low Cost, Stand-Alone, In-situ, PV Curve Tracer” at the 2nd International Conference on Photovoltaic Science and Technology. The workshop, which was held virtually 30 November through 2 December 2020, was originally scheduled to be in-person in Ankara, TURKEY.

The paper aims to reduce the cost of a flexible and scalable i-v curve tracer that was developed previously in the REAPERLab. The system includes three main components: a source measuring unit, multiple relay boards, and a raspberry pi. The system enables four modes of operation: F1 is used to test individual PV modules, while F2 is used to perform a time-sequence test of the PV modules. F3 is used to test the interconnection of PV modules, and F4 is used to run a time-sequenced test of PV interconnections.

Dr. Wesam Rohouma presents a research paper at the 2nd International Conference on Photovoltaic Science and Technology (PVCON).

Dr. Wesam Rohouma, Professor Robert S. Balog, Ph.D. student Mr. Aaqib Peerzada and Professor Miroslav Begovic presented their paper entitled “Voltage Profile Enhancement Using Capacitor-less D-STATCOM to Increase PV Penetration in Distribution Network Under Transient Cloud Conditions” at the 2nd International Conference on Photovoltaic Science and Technology. The workshop, which was held virtually 30 November through 2 December 2020, was originally scheduled to be in-person in Ankara, TURKEY.

While the grid-connected PV systems deliver electric energy closer to the consumer, thus aiding the paradigm shift from a centralized to distributed generation, the stochastic nature of PV output has created new challenges in the operation and maintenance of electric distribution systems. Reactive power compensation can be used to keep the voltage profile on the network within the allowable limits set by the relevant standards. A capacitor-less approach is used in this paper instead of the traditional techniques that are based on electrolytic capacitor banks with well-known failure rates.

In this paper, a capacitor-less distribution static synchronous compensator (D-STATCOM) based matrix converter (MC) is proposed for use in low voltage distribution network. This technology is controlled using finite-set model predictive control, the compensator device can operate in a variety of modes and can be deployed and dispatched as needed in the distribution system. Experimental results show the effectiveness of the proposed technology in improving voltage profile in the low voltage distribution networks during cloud cover. 

This publication was made possible by NPRP grant # 9-204-2-103 from the Qatar National Research Fund (a member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors. The authors acknowledge and thank Prof. Pat Wheeler and Prof. Lee Empringham from the power electronics and machine control group at the University of Nottingham, UK, for their collaboration on the matrix converter prototype design and fabrication.

Sawsan Shukri presents a research paper at the 2nd International Conference on Photovoltaic Science and Technology (PVCON).

Ph.D. student Ms. Sawsan Shukri, undergraduate research assistant Mr. Safin H. Bayes, Ph.D. student Mr. Lance Alpuerto, and postdoctoral researcher Dr. Morcos Metry presented their paper entitled, “Non-Planar Photovoltaic Testbed Based on in-situ Parameter Extraction for PV Simulation & Emulation” at the 2nd International Conference on Photovoltaic Science and Technology. The workshop, which was held virtually 30 November through 2 December 2020, was originally scheduled to be in-person in Ankara, TURKEY.

The paper aims to present an experimental testbed for non-planar PV structures that can be used to collect the in-situ experimental data to examine various PV interconnections and use the data to characterize and emulate operation for research and development.

This publication was made possible in part by PDRA grant # 5-0422-19004 from the Qatar National Research Fund (a member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors.

Nabila Elbeheiry presents a research paper at the 2nd International Conference on Photovoltaic Science and Technology (PVCON).

Research assistant Ms. Nabila Elbeheiry, undergraduate research assistants Mr. Abdelrahman Amer and Mr. Seif Elgazar, Ph.D. student Ms. Sawsan Shukri, and postdoctoral researcher Dr. Morcos Metry presented their paper entitled “Techno-economic Evaluation of Residential PV Systems in Oil/Gas-Rich Economies: A Case Study of Qatar & Texas” at the 2nd International Conference on Photovoltaic Science and Technology. The workshop, which was held virtually 30 November through 2 December 2020, was originally scheduled to be in-person in Ankara, TURKEY.

The paper presents a techno-economic analysis based on the implementation of a residential rooftop photovoltaic system in oil and gas-based economies. Two case studies were used as examples of implementation in different parts of the world: Texas, USA, and Doha, Qatar. In both cases, a long-term simulation of a house is used to determine the economic feasibility of residential PV. Factors like generation and load profiles, cost of grid consumption, cost of materials, and house size were taken into account in this study.

This publication was made possible in part by PDRA grant # 5-0422-19004 from the Qatar National Research Fund (a member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors.

Fatima Al-Janahi presents a research paper at the 2nd International Conference on Photovoltaic Science and Technology (PVCON).

Research assistant Ms. Fatima Al-Janahi, Ph.D. student Ms. Sawsan Shukri, and Mr. Kais Abdulmawjood presented their paper entitled “Characterizing DC Arcs for Photovoltaic Arc Fault Detection” at the 2nd International Conference on Photovoltaic Science and Technology. The workshop, which was held virtually 30 November through 2 December 2020, was originally scheduled to be in-person in Ankara, TURKEY.

The paper aims to demonstrate how to perform multiple arc generation experiments using the pull-apart method that includes different parameter combinations. Some factors that influence the electrical characteristics of the arc are the following: the electrode material and geometry, electrical current and voltage, and the electrode separation gap profile. The analysis of the results can be help researchers to identify key distinguishing features of the arc that can be used to design a reliable arc detector.

This publication was made possible by QNRF grant # UREP24-023-2-010 from the Qatar National Research Fund (a member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors.

Minjeong Kim presents research paper at the Twenty-First IEEE Workshop on Control and Modeling for Power Electronics (COMPEL).

Ph.D. student Ms. Minjeong Kim presented her paper entitled “Commutation Method for a Three-Phase Current-Sourced High-Frequency AC-link Inverter” at the twenty-first IEEE Workshop on Control and Modeling for Power Electronics on November 10, 2020. The workshop, which was held virtually, was originally scheduled to be in-person in Aalborg, DENMARK.

The paper proposes a new commutation method for a three-phase current-sourced high-frequency ac-link inverter. The paper includes the basic operation principles of the topology and the requirements for current commutation. The publication is based on research supported by the US Army Research Laboratory through the National Science Foundation Industry/University Cooperative Research Center for Next Generation Photovoltaics (IIP-1624539).

Dr. Wesam Rohouma presents a research paper at the Twenty-First IEEE Workshop on Control and Modeling for Power Electronics (COMPEL).

Assistant Research Scientist Dr. Wesam Rohouma and Postdoctoral Researcher Dr. Morcos Metry presented their research on improving the reliability of the Capacitorless D-STATCOM in the distribution networks on November 10, 2020. The workshop, which was held virtually, was originally scheduled to be in-person in Aalborg, DENMARK.

This paper presents a method based on Model Predictive Control (MPC) to reduce switching losses in the converter by controlling the error margin size (aka penalizing fidelity) while maintaining acceptable operation within IEEE harmonics standards. This work results show a reduction in switching frequency by over 30%, which results in reducing switching losses and improving the reliability of the system.

This publication was made possible by NPRP grant # 9-204-2-103 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. The authors acknowledge and thank Prof. Pat Wheeler and Prof. Lee Empringham from the power electronics and machine control group at the University of Nottingham, UK, for their collaboration on the matrix converter prototype design and fabrication.

Dr. Morcos Metry presents research paper at the Twenty-First IEEE Workshop on Control and Modeling for Power Electronics (COMPEL).

Postdoctoral Researcher Dr. Morcos Metry, and Ph.D. Candidate Ms. Minjeong Kim presented their research on a closed-loop controller for the ripple port module integrated inverter at the twenty-first IEEE Workshop on Control and Modeling for Power Electronics on November 10, 2020. The workshop, which was held virtually, was originally scheduled to be in-person in Aalborg, DENMARK.

This paper presents a closed-loop controller using Model Predictive Control (MPC) for the ripple port module integrated inverter (RP-MII). The invention, development, and improvement of the ripple port inverters have been led by multiple REAPER lab members to mitigate the reliability issues associated with using bulky electrolytic capacitors at the dc link to filter out double frequency ripple. One challenge with the ripple port inverter has been its closed-loop control requiring multiple complex control loops with various objectives. This work presents a framework using MPC’s multi-objective feature to regulate the RP-MII using a single control loop. This work shows a reduction in dc-link capacitor sizes required from 800 uF to 16 uf, improving the RP-MII’s overall reliability as more reliable film capacitors could be employed.

This publication is based on research supported by the US Army Research Laboratory through the National Science Foundation Industry/University Cooperative Research Center for Next Generation Photovoltaics (IIP-1624539). This publication was also made possible in part by PDRA grant # 5-0422-19004 from the Qatar National Research Fund (a member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors.

Ph.D. Final Examination: Dr. Lance Alpuerto

REAPER Lab congratulates Dr. Lance Alpuerto for successfully defending his Ph.D. dissertation, “Non-Planar Photovoltaic Surfaces: Modeling, Optimization, and Application.” His research investigated the application of flexible thin-film photovoltaic (PV) materials conformed to curved surfaces. He developed a comprehensive modeling methodology to evaluate the potential advantages and disadvantages when applied to a non-planar surface. Using a multi-physics based approach, the major factors that influence PV applications are evaluated to predict the real-world operating conditions and electrical behaviors. The unique issue of self-shading, causing a mismatch in current density, on curved applications is addressed by creating an approach to optimize the interconnection strategy for improved performance. His work details a standardized and scale-invariant modeling foundation for the purpose of promoting future investigations into non-planar PV technologies.

Lance received his B.A. in Mathematics from Lyon College in Batesville, AR, in 2013 and then M.S. in Electrical Engineering from Texas A&M University at College Station, TX in 2016.

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